A direct current/direct current (DC/DC) converter composed of a high-side switch and a low-side switch is well known as a power supply circuit. A half-bridge configuration in which two transistors, namely, a high-side transistor and a low-side transistor, are connected is used not only in a DC/DC converter but also in an audio class-D amplifier and the like, and research and development has been actively carried out to improve power conversion efficiency and miniaturize the circuit.
Patent Literature (PTL) 1 discloses a configuration in which two nitride semiconductors that are connected in a half-bridge configuration are formed on a common substrate. This configuration is advantageous in that the half-bridge configuration can be formed within a single package, and thus the circuit can be miniaturized.
Patent Literature 2 discloses, as a technique for miniaturization of power semiconductor elements, a so-called pad-on element structure in which electrode pads are formed above an active region. This technique does not require the pads to be formed on the sides of the device as in Patent Literature 1, and thus enables a small chip area.
Furthermore, flip-chip mounting is another technique that contributes to the miniaturization of circuits. Flip-chip mounting provides an advantage of a smaller footprint than interconnect bonding. Also, flip-chip mounting provides an advantage of reducing interconnect resistance and interconnect inductance because interconnects can be shortened as compared to using wires.